Things Flung from the Sun
Our sun is a complex engine. The storms on the sun that sometimes erupt into space not only provide interesting viewing for solar observers, but they can also generate magnetic disturbances on the Earth, causing a disruption of communications and power outages in northern latitudes.
In an effort to arrive at better methods of predicting how energetic solar wind particles are generated, scientists are conducting an extensive study of micro-flares - small eruptions of gas and charged particles on the sun's surface that arc from one spot to another. An astronomer at Louisiana State University is investigating the global interaction of the solar wind with the earth's magnetic field using a 3-D electromagnetic particle code. This is expected to provide insights into predicting magnetic storms and minimizing the damage they do.
Another solar researcher at LSU views the sun in "neutrino light." Neutrinos are particles which have so little mass that it's conceivable one of them could go through a light-year-thick piece of lead (if such a thing existed!) without hitting anything. Yet there are so many of them that they can be identified using neutrino detectors - huge tanks of water buried deep underground to keep any other type of radiation from interacting with the water molecules. There are currently five operating neutrino detectors on various parts of the Earth. The world's largest neutrino detector, the Super Kamiokande detector near Toyama, Japan, began operation in 1997. A joint U.S./Canadian neutrino detector started collecting data in 1998, and another is being built in Italy.
A neutrino is emitted every time two hydrogen atoms fuse to form a helium atom, which is the basic reaction that drives the sun. Because there are so many neutrinos, the odds are good that some of them will hit a water molecule. When that happens, sensitive detectors lining the tanks pick up the flash, even during nighttime hours when the sun is on the opposite side of the earth.
The sun is so large and dense that it takes 50,000 years for the energy from reactions taking place in its core to reach its surface. But since neutrinos fly through virtually anything, they provide an indication of what's going on deep inside the solar furnace. Physicists have calculated the number of hydrogen atoms fusing into helium atoms to produce the amount of energy output from the sun. Since each fusion reaction produces one neutrino, the number of neutrinos detected should correlate to the sun's energy output.
But it doesn't.
"We're seeing fewer than a third of the neutrinos theory would predict," said Robert Svoboda, one of the LSU researchers. That means scientists do not have a complete understanding of either solar or neutrino physics, or the sun is shutting down. However, Svoboda seriously doubts the sun is shutting down. Solar scientists expect to reach an answer concerning the missing neutrinos within the next few years. But they first have to untangle the neutrino physics from the solar physics. So far there's no evidence that any unusual neutrino physics is going on in the sun, but the data is under review.
With due regard to these mysteries, our sun has been around for a few billion years, all the while "doing its thing". But we now have instruments available to detect these puzzling things. Yet there's a certain amount of paranoia about the year 2000 and eruptions on the sun that will occur at the millenium. One expects hysteria in the tabloids lining the supermarket checkout aisles, but even the legitimate press and radio stations have carried stories about this. For example, here's a quote from the Chicago Tribune of June 3, 1999: "...scientists explained that huge and violent storms on the surface of the sun next year will likely be more powerful than they have been in a decade and could knock out cell phones and cause power blackouts here on our planet". This was printed without any clarification, so the man in the street may become alarmed about the massive solar flares that will rake the Earth. The truth? There will be flares and they will be more powerful than they have been in the last decade, but there is always an increase in the output of solar particles during the peak of each eleven-year cycle. It is sheer coincidence that the peak of the current solar cycle will take place during the year 2000 (around April). If anything, the current cycle appears to be somewhat less intense than the average of others in this century.
There's still a lot to be learned about our sun, but scientists predict that it will remain just as benign as it has been throughout its long history. It will be more active in the year 2000, simply because it's the normal peak of a normal solar cycle. And if we're really lucky, we'll be treated to some great northern lights displays.Published in the November 1999 issue of the NightTimes